Arithmetic/Introduction to Arithmetic
Whether you're a scientist or a shopper you need arithmetic. There are all sorts of situations where it is useful to be able to count, measure and communicate quantities. Arithmetic is the study of numerical quantities. At least a basic understanding of arithmetic is fundamental in the study of algebra and all other mathematical studies. This book assumes that the reader already understands some mathematics but wishes to relearn it in a more formal manner.
Basic Operations 
There are four basic operations one can perform on different numeric quantities (as well as other mathematical objects which you will encounter later). These are:
- addition (+)
- subtraction (−)
- multiplication (×)
- division (÷)
It is also important to understand that the equals sign (in this book, '=' ) means that the things on both sides are of equal value, and that = is not an operator.
When you see an = sign, say to yourself Same value, different appearance.